There presently is a need to provide security for data and software. For example, in bank terminals, data are entered using a touchpad or derived by a card reader (e.g., magnetic card reader). These data are used to make a secure transaction. Security is necessary for such a transaction and access to the data must be protected.
To ensure that the data are not tampered with, stolen, or otherwise accessed without authorization, the data are commonly encrypted prior to transmission. However data or software could still be accessed prior to encryption, as by accessing the leads of an integrated circuit to which the unencrypted data are first sent.
In prior devices a three dimensional mesh has been used to enclose a set of integrated circuits and prevent tampering. For example, U.S. Pat. No. 6,646,565 discloses a device for security of electronic circuits in which an electronic device is encased between a first and a second circuit board each of which has a serpentine conductive layer. A tamper detection circuit is connected to the conductive layer to detect circuit tampering. The entire device is wrapped in a mesh. Any tampering with the circuit boards or the mesh is sensed by detection of disturbance in a current flowing through a security layer in the circuit boards and mesh. This current disturbance signals a security system to erase sensitive data, such that it will not be intercepted. Other similar devices include U.S. Pat. Nos. 4,593,384; 4,691,350; and 4,807,284.
U.S. Pat. No. 5,406,630 discloses a tamper proof integrated circuit (IC) device. The package and lid include heavy metals to prevent both x-ray radiation and infrared detection of the functioning of the chip. This effectively provides an electrical shield of the workings of the IC.
U.S. Pat. No. 6,396,400 discloses a security system for protecting a data storage device. The data storage device is enclosed in a first housing, which is mounted within and separated from a second housing by a number of support structures. A vacuum is created in an interstitial space between the first housing and the second housing. Breach of the second housing causes a pressure change. The pressure change is detected by a sensor which signals the data storage device to act to protect the data from tampering.
These disclosed devices are complex and expensive. Alternative, simpler solutions are sought.